If I boil it down, I think 16GB is reaching the point of being obsolete (due to increasing size/memory usage of apps and games) and when that happens you WILL notice the degradation in performance. So, if you plan to keep this system any decent length of time (e.g. 1.5 - 2+ years) rather than switching to AM5&DDR5, then I'd just do it now while the memory upgrade is relatively cheap and widely available.
The technicalities of losing performance with higher latency and fewer ranks is not a big deal when/if you're running out of memory, but if you can avoid it: I'd do it. Having dual rank 16x2 sticks will likely gain you more performance than the latency, FYI.
Be careful with the 4060 Ti, they're barely faster than the 3060 Ti (especially in a PCI-E 3.0 board) and the 16GB version is way overpriced.
So far as I know the new cards will be released over the next months, but RDNA4 is midrange only, so more likely to be appealing than nvidia, since I'd expect them to go high-end first.
